Various optical displacement sensors generally referred to as encoders utilize a periodic scale structure that allows the displacement of an encoder readhead relative to the scale to be determined by illuminating the scale with light and imaging a periodic pattern of light. U.S. Pat. Nos. 7,186,969; 7,307,789; and 7,435,945, each of which is hereby incorporated herein by reference, disclose various encoder configurations that utilize either singly or doubly telecentric imaging systems for imaging the periodic pattern of light and sensing displacement of the periodic scale structure. Telecentric imaging systems provide certain desirable features in such encoders. However, existing encoders that use telecentric imaging fail to provide combinations of economy, robustness, accuracy, and compact dimensions that are desirable for a number of applications. Therefore, improved configurations for encoders that use telecentric imaging are desirable.